<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        .box{
            width: 600px;
            height: 600px;
            display: grid;
            border: 1px solid violet;
            grid-template-rows: 1fr 1fr 1fr;
            grid-template-columns: 1fr 1fr 1fr;
            /* grid-gap: 20px 20px; */

            grid-template-areas: 'a a c' 
                                 'd e e'
                                 'd h i';
        }
        .box div{
            border: 1px dashed skyblue;
        }
        .box div:nth-child(2){
            grid-area: a;
        }
        .box div:nth-child(6){
            grid-area: d;
        }
        .box div:nth-child(3){
            grid-area: e;
        }
    </style>
</head>
<body>
    <div class="box">
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
        <div>5</div>
        <div>6</div>
    </div>
</body>
</html>